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-------------------------- 2773 - FINE STRUCTURE CONSTANT
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- I believe in solving the Big problems. Like, “what is the weight of the universe?” My wife solves all the smaller problems. Technically, we can not “weigh” the universe, but, we can try to figure out the “mass” of the universe.
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- It is a difficult thing to measure. To do it you need to count not just stars and galaxies, but dark matter, diffuse clouds of dust and even wisps of neutral hydrogen in intergalactic space.
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- Knowing the mass of the universe is central to understanding its history and evolution. While dark energy drives the universe to expand, matter tries to keep the universe from expanding. Together they form an average density of matter and energy in the universe, known as the “cosmic density parameter“.
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- One way to measure this density is using at the “Cosmic Microwave Background”, (CMB). This remnant glow from the Big Bang has small variations in temperature. The scale of these fluctuations tells us the rate of cosmic expansion, which in turn lets us know the cosmic matter density.
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- Another way to weigh the universe is to look at how the light of distant galaxies is deflected by galaxies. It’s an effect known as “gravitational lensing“. The challenge with this method is determining which light is lensed and which is not. To do that we would need to compare the distorted shape of the galaxy we see with the actual shape of the galaxy, which we don’t know.
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- It is not possible to make a comparison for a single galaxy, but we can compare them statistically with many galaxies. Since we know the shape of an average galaxy, we can compare this to the lensed shapes we see to get a statistical measure of how much lensing occurs.
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- While the lensing effect gives a statistical measure of the amount of mass between us and a distant galaxy, it doesn’t give the ‘cosmic density“. For that, you need to know how far away the galaxy is. The greater the distance, the more mass you would expect between it and us. To determine galactic distances we measure the redshifts at several wavelengths.
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- The result is a cosmic density parameter that differs slightly from that found from the CMB. This is not the first time we’ve seen a strange disagreement in cosmology. In the “standard model“, it is assumed that the amount of dark energy in the universe is constant. But this latest data fit an alternative model where dark energy changes over time. It increases over time.
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- Not only does a universal constant of universe expansion seem annoyingly inconstant at the outer fringes of the cosmos, it occurs in only one direction. Astrophysicists continue to find these hints that one of the cosmological constants is not so constant after all.
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- New measurements of light emitted from a quasar 13 billion light years away reaffirm past studies that found tiny variations in the fine structure constant for Universe expansion.
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- The fine structure constant is a measure of electromagnetism and it is one of the four fundamental forces in nature (the others are gravity, weak nuclear force and strong nuclear force). The fine structure constant is the quantity that physicists use as a measure of the strength of the electromagnetic force.
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- The fine structure constant is a dimensionless number and it involves the speed of light, the “Planck's constant” and the electron charge, and it is a ratio of those things. It is the number that physicists use to measure the strength of the electromagnetic force.
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- The Fine Structure Constant = 1 /137
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- The Fine Structure Constant = e^2 / 4 *pi* Eo * h * c
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- The Fine Structure Constant = mo * c * e^2 / 2 * h
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- See Review 2407 to learn what all these symbols and fomulas mean. And , Review 1473 which is the math that makes the atom work.
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- The electromagnetic force keeps electrons orbiting around a nucleus in every atom of the universe. It was believed to be an unchanging force throughout time and space. But anomalies in the fine structure constant have been found whereby electromagnetic force measured in one particular direction of the universe seems ever so slightly different.
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- The fine structure constant was different in certain regions of the universe. Not just as a function of time, but actually also in direction in the universe.
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- The most distant quasars that we know of are about 12 to 13 billion light years from us.
If you can study the light in detail from distant quasars, you're studying the properties of the universe as it was when it was in its infancy, only a billion years old.
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- The universe then was very different. No galaxies existed, the early stars had formed but there was certainly not the same population of stars that we see today. And there were no planets.
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- One such quasar that enabled astronomers to probe back to when the universe was only a billion years old had never been done before. Four measurements were made of the fine constant along the line of sight to this quasar.
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- There could be a directionality in the universe, which is very weird indeed. The universe may not be “isotropic’ in its laws of physics that states that the universe is the same, statistically, in all directions.
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- But in fact, there could be some direction or preferred direction in the universe where the laws of physics change, but not in the perpendicular direction. In other words, the universe in some sense, has a dipole structure to it.
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- In one particular direction, we can look back 12 billion light years and measure electromagnetism when the universe was very young. Putting all the data together, electromagnetism seems to gradually increase the further we look, while towards the opposite direction, it gradually decreases.
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- In other directions in the cosmos, the fine structure constant remains just that, constant. These new very distant measurements have pushed our observations further than has ever been reached before.
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- In what was thought to be an arbitrarily random spread of galaxies, quasars, black holes, stars, gas clouds and planets—with life flourishing in at least one tiny niche of it—the universe suddenly appears to have the equivalent of a north and a south.
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- Other independent observations made using X-ray astronomy also seem to align with the idea that the universe has some sort of directionality. The X-ray properties were mearsued of galaxies and clusters of galaxies and cosmological distances from Earth. They found that the properties of the universe in this sense are not isotropic and there's a preferred direction. This direction coincides with the quasar measurements.
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- For a long time, it has been thought that the laws of nature appear perfectly tuned to set the conditions for life to flourish. The strength of the electromagnetic force, in other words the fine structure constant, is one of those quantities. If it were only a few percent different to the value we measure on Earth, the chemical evolution of the universe would be completely different and life may never have got going.
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- It raises the question: does this "Goldilocks' situation, where fundamental physical quantities like the fine structure constant are 'just right' to favor our existence, apply throughout the entire universe?
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- If there is a directionality in the universe, and if electromagnetism is shown to be very slightly different in certain regions of the cosmos, the most fundamental concepts underpinning much of modern physics will need revision.
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- Our standard model of cosmology is based on an isotropic universe, one that is the same, statistically, in all directions.
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- That standard model itself is built upon Einstein's theory of gravity, which itself explicitly assumes constancy of the laws of Nature. If such fundamental principles turn out to be only good approximations, the doors are open to some very exciting, new ideas in physics.
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- Some physicists believe this is the first step towards a far larger study exploring many directions in the universe, using data coming from new instruments on the world's largest telescopes.
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- New technologies are now emerging to provide higher quality data, and new artificial intelligence analysis methods will help to automate measurements and carry them out more rapidly and with greater precision.
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- Students today certainly live in interesting times. Thankfully the FSC is just right to pursue some answers.
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------------------------------- Other Reviews available upon request:
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- 2407 - FINE STRUCTURE CONSTANT - is this one of the fundamental constants in the Universe? The fine structure constant number was discovered in 1916 by Arnold Sommerfeld and has remained a mystery ever since. Fifty years after Sommerfeld Richard Feynman said, “ it is one of the greatest damn mysteries of physics.”
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- 1473 - The math that makes an atom work. It is over 100 years of discovery.
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- 1336 - The mystery of the fine structure constant. Alpha = 0.0072973531. Does this mean that the Universe is not homogeneous and isotropic? Is Dark Matter and Dark Energy different in different parts of the Universe? Does the Universe have neighborhoods that are fundamentally different from each other ? Do we really live in a special place in the Universe? This is a mystery beyond belief. Some answers here could turn astronomy and physics on its head. An announcement will be made shortly, stay tuned.
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- July 13, 2020 2773
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--------------------- Tuesday, July 14, 2020 -------------------------
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